Method for supporting efficient PDU session activation and deactivation in cellular networks

A method performed by an access and mobility management function (AMF) entity for managing a protocol data unit (PDU) session in a wireless communication system, comprising:

• receiving, from a session management function (SMF) entity, a first message for subscribing to a service notifying a location change of a terminal for a specific area, the specific area being identified based on a list of tracking areas of the terminal;
• identifying the location change of the terminal for the specific area based on the first message;
• and
• transmitting, to the SMF entity, a second message including information on the location change of the terminal,
• wherein the information on the location change of the terminal is used by the SMF entity to determine whether to maintain at least one user plane function (UPF) associated with the PDU session for the terminal in an idle state,
• wherein the specific area is determined by the SMF entity, and
• wherein the at least one UPF includes at least one intermediate UPF.

A session management function (SMF) entity in a wireless communication system, comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to control to:
• determine a specific area, the specific area being identified based on a list of tracking areas of a terminal,
• transmit, to an access and mobility management function (AMF) entity, a first message for subscribing to a service notifying a location change of the terminal for the specific area,
• receive, from the AMF entity, a second message including information on the location change of the terminal, and
• determine whether to maintain at least one user plane function (UPF) associated with a protocol data unit (PDU) session for the terminal in an idle state, based on the information on the location change of the terminal,
• wherein the at least one UPF includes at least one intermediate UPF.

An access and mobility management function (AMF) entity in a wireless communication system, comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to control to:
• receive, from a session management function (SMF) entity, a first message for subscribing to a service notifying a location change of a terminal for a specific area, the specific area being identified based on a list of tracking areas of the terminal,
• identify the location change of the terminal for the specific area based on the first message, and
• transmit, to the SMF entity, a second message including information on the location change of the terminal,
• wherein the information on the location change of the terminal is used by the SMF entity to determine whether to maintain at least one user plane function (UPF) associated with a protocol data unit (PDU) session for the terminal in an idle state,
• wherein the specific area is determined by the SMF entity, and
• wherein the at least one UPF includes at least one intermediate UPF.